Vehicle restraints are commonly used in association with a loading dock to prevent the accidental movement of a truck away from a loading dock during a loading operation. The conventional vehicle restraint includes a hook-like restraining member that can be moved from a storage position to an operative position where the hook extends outwardly from the loading dock and the tip of the hook will be in a position to be engaged by the ICC bar of the truck to prevent the truck from moving away from the dock.
The ICC bar is a horizontal bar or beam, located beneath the rear end of the truck bed to prevent underriding of the truck by an automobile in the event of a rear end collision. All trailer-type trucks, as well as city delivery trucks, are required to have an ICC bar, but the height of the bar above the ground, as well as the position of the ICC bar from the rear end of the truck bed can vary substantially from truck-to-truck.
It has been found that when the hook-like restraining member is in its operative position the outer tip of the hook may be spaced a substantial horizontal distance outwardly of the ICC bar and this is particularly true where the ICC bar is located immediately adjacent the rear end of the truck. If the tip of the hook is spaced outwardly from the ICC bar, the truck can rock in a fore and aft direction during a loading operation as material handling equipment, such as a fork lift truck, moves between the dock and the truck bed. This rocking action can cause undue stress on the restraining member and the ICC bar and in certain extreme situations, forward rocking of the truck can cause the lip of a dockboard, which bridges the gap between the loading dock and the truck bed, to fall out of engagement with the truck bed. Because of this, there has been a need for a vehicle restraint, in which the outer tip of the hook can be brought into tight engagement with the ICC bar during a loading operation to prevent fore and aft rocking of the truck.
Another consideration in the design of a vehicle restraint is a provision to accommodate vertical float of the truck bed and ICC bar during a loading operation. As a fork lift truck moves onto the truck bed, and as cargo is applied to the truck bed, the truck bed and ICC bar will lower. Conversely, when cargo is removed from the truck bed, the truck bed and ICC bar will rise. Because of this vertical float of the ICC bar during a loading operation, a vehicle restraint must incorporate a mechanism which will accommodate the float, so as to maintain the hook or restraining member in engagement with the ICC bar at all times during the floating action.